Image projection apparatus

ABSTRACT

An image projection apparatus includes a light source, light from which is used to project an image, and a holding member configured to hold the light source. The holding member includes a handle portion, and the handle portion includes a first flow path for flowing air.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to and incorporates by referencethe entire contents of Japanese Patent Application No. 2011-242927 filedin Japan on Nov. 4, 2011.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image projection apparatus.

2. Description of the Related Art

Conventionally, there is known an image projection apparatus providedwith an image forming unit to form an image with light emitted from alight source on the basis of image data from a personal computer (PC),video camera or the like, so that the image is projected and displayedon a screen or the like.

As the light source of the image projection apparatus, a halogen lamp, ametal halide lamp, a high pressure mercury lamp and the like may beused. These kinds of lamps become high temperature when emitting light.Therefore, the image projection apparatus is provided with a lightsource cooling unit for cooling the light source by flowing air to thelight source by an air flowing device such as a blower and a fan (e.g.Japanese Patent Application Laid-open No. 2003-5292 and InternationalPublication No. WO02/097529).

The light source reaches its end of lifetime after use over time.Therefore, the image project apparatus has a configuration allowing forthe replacement of the light source by the user. Specifically, an outercase of the image projection apparatus has a replacement opening fordetaching and attaching the light source unit including the light sourcefrom and to a main body of the apparatus. An access cover which is anopenable and closable cover to open and close the replacement opening isalso provided. When the user replaces the light source, the user removethe access cover from the outer case, grab a handle formed on the lightsource unit to pull out the light source unit from the replacementopening, and insert a new light source unit from the replacement openingto attach the new light source unit to the main body. Thus, the lightsource unit is replaced.

In many cases, the light source unit is provided with a handle allowingfor the user to grab it by hand or pinch it by fingers for the improvedoperability in replacing the light source unit. However, the handle ofthe light source unit becomes also high temperature due to heatconductance or heat radiation from the light source. As a result, whenthe light unit is to be replaced due to the end of lifetime of the lightsource during operation of the image projection apparatus, the usercannot grab or pinch the handle. Thereby, the user has to wait toreplace the light source unit until the handle is cooled sufficiently.Therefore, the downtime of the apparatus is disadvantageously long.

SUMMARY OF THE INVENTION

It is an object of the present invention to at least partially solve theproblems in the conventional technology.

An image projection apparatus includes a light source, light from whichis used to project an image, and a holding member configured to hold thelight source. The holding member includes a handle portion, and thehandle portion includes a first flow path for flowing air.

A light source unit attachable to and detachable from a main body of animage projection apparatus includes a light source, light from which isused to project an image, and a holding member configured to hold thelight source. The holding member includes a handle portion, and thehandle portion includes a first flow path for flowing air.

The above and other objects, features, advantages and technical andindustrial significance of this invention will be better understood byreading the following detailed description of presently preferredembodiments of the invention, when considered in connection with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a perspective view illustrating a projector and a projectionplane according to an embodiment;

FIG. 2 is a view illustrating light paths from the projector to theprojection plane;

FIG. 3 is a perspective view schematically illustrating an innerstructure of the projector;

FIG. 4 is a perspective view schematically illustrating a light sourceunit;

FIG. 5 is an exploded view perspectively and schematically illustratingthe light source unit;

FIG. 6 is a perspective view illustrating optical system componentshoused in a lighting unit, illustrating with other units;

FIG. 7 is a perspective view illustrating the lighting unit, aprojection lens unit, and an image forming unit, viewed from a directionindicated by an arrow A in FIG. 6;

FIG. 8 is a view illustrating light paths in the lighting unit;

FIG. 9 is a perspective view illustrating the image forming unit;

FIG. 10 is a perspective view illustrating a first optical unit with thelighting unit and the image forming unit;

FIG. 11 is a section along A-A line in FIG. 10;

FIG. 12 is a perspective view illustrating a second optical system heldin a second optical unit, illustrating with the projection lens unit,the lighting unit, and the image forming unit;

FIG. 13 is a perspective view illustrating the second optical unit withthe first optical unit, the lighting unit, and the image forming unit;

FIG. 14 is a perspective view illustrating light paths from the firstoptical system to the projection plane;

FIG. 15 is a schematic view illustrating an arrangement of units in theapparatus;

FIG. 16 is a view illustrating a usage example of the projectoraccording to the embodiment;

FIG. 17 is a view illustrating a usage example of a conventionalprojector;

FIG. 18 is a view illustrating a usage example of a projector in which alight source and a lighting unit are aligned in a direction orthogonalto a projection plane;

FIG. 19 is a view illustrating another usage example of the projectoraccording to the embodiment;

FIG. 20 is a perspective view illustrating the projector from aninstallation side thereof;

FIG. 21 is a perspective view illustrating a state that an access coveris removed from the apparatus;

FIG. 22 is a view illustrating airflows in the projector;

FIG. 23 is a view illustrating the configuration illustrated in FIG. 22more specifically;

FIG. 24 is a section along A-A line in FIG. 23;

FIG. 25 is a section along B-B line in FIG. 23;

FIG. 26 is a perspective view illustrating a cooling unit for cooling aDMD and the like, illustrating with the lighting unit and the lightsource unit;

FIG. 27 is a longitudinal section of FIG. 26;

FIG. 28 is a perspective view illustrating a horizontal duct and thelight source unit with a base component;

FIG. 29 is a view illustrating airflows from the horizontal duct to alight source bracket, viewed from a lower side of the base component;and

FIG. 30 is a perspective view illustrating airflows from the horizontalduct to the light source bracket, viewed from an upper side of the basecomponent.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, embodiments of a projector as an image projection apparatusaccording to the present invention will be described with reference tothe accompanying drawings. FIG. 1 perspectively illustrates a projector1 and a projection plane 101 such as a screen according to anembodiment. Incidentally, in the following explanation, a normal linedirection of the projection plane 101 is referred to as X direction, ashort axis direction (vertical direction) of the projection plane 101 isreferred to as Y direction, and a long axis direction (horizontaldirection) of the projection plane 101 is referred to as Z direction.

As illustrated in FIG. 1, a transmissive glass 51 from which aprojection image P is emitted is disposed at a top surface of theprojector 1. The projection image P emitted from the transmissive glass51 is projected on the projection plane 101 such as a screen.

Furthermore, at the top surface of the projector 1, an operating part 83by which a user operates the projector 1 is disposed. At a side surfaceof the projector, a focus lever 33 for a focus adjustment is disposed.

FIG. 2 illustrates light paths from the projector 1 to the projectionplane 101.

The projector 1 is provided with (i) a light source unit including alight source and (ii) an image forming part A to form an image by usinga light from the light source. The image forming part A includes (i) animage forming unit 10 provided with a DMD (Digital Mirror Device) 12 asan image forming element and (ii) a lighting unit 20 for reflecting thelight from the light source to the DMD 12 so that an optical image isgenerated. The projector 1 is also provided with a projection opticalsystem B to project the image on the projection plane 101. Theprojection optical system B has at least one transmissive refractingoptical system and includes (i) a first optical unit 30 provided with afirst optical system 70 which is a coaxial optical system having apositive power and (ii) a second optical unit 40 provided with areflecting mirror 41 and a concave mirror 42 having a positive power.

The DMD 12 is irradiated with the light from the light source by thelighting unit 20. The light irradiated by the lighting unit 20 ismodulated to form the image. The optical image formed by the DMD 12 isprojected on the projection plane through the first optical system 70 inthe first optical unit 30, and the reflecting mirror 41 and the concavemirror 42 in the second optical unit 40.

FIG. 3 schematically and perspectively illustrates an internal structureof the projector 1.

As illustrated in FIG. 3, the image forming unit 10, the lighting unit20, the first optical unit 30, the second optical unit 40 are aligned inY direction in the figure among directions parallel to the projectionplane and an image plane of the projection image. The light source unit60 is disposed at a right side in the figure of the lighting unit 20.

Incidentally, in FIG. 3, reference numerals 32 a 1 and 32 a 2 refer tolegs of a lens holder 32 of the first optical unit 30, and referencenumeral 262 refers to a screw clamp portion for screwing (fixing byscrew) the image forming unit 10 to the lighting unit 20.

Next, each unit structure will be described.

First, the light source unit 60 will be described.

FIG. 4 schematically and perspectively illustrates the light source unit60. FIG. 5 is a schematic exploded view of the light source unit 60.

The light source unit 60 includes a light source bracket 62 which is aholding member for holding the light source 61. A light source 61 suchas a halogen lamp, a metal halide lamp and a high pressure mercury lampis mounted on the light source bracket 62. The light source bracket 62is provided with a connector portion 62 a for connecting with a powersource side connector connected to a power source unit 80 (see FIG. 15).

A holder 64, which holds a reflector and the like, is screwed to theupper side of the light source bracket 62 on a light emitting side ofthe light source 61. The holder 64 has an emitting window 63 at anopposite side to a side where the light source 61 is disposed. The lightemitted from the light source 61 is collected to the emitting window 63by the reflector 67, which is held by the holder 64, and emitted fromthe emitting window 63.

Light source positioning portions 64 a 1 to 64 a 3 are disposed at a topside and at X direction both ends of a bottom side of the holder 64, forpositioning the light source unit 60 relative to a lighting bracket 26(see FIG. 7) of the lighting unit 20. The light source positioningportion 64 a 3 disposed at the top side of the holder 64 is a protrusionor has a protrusion-like structure. The light source positioningportions 64 a 1 and 64 a 2 disposed at both ends of the bottom side ofthe holder 64 are holes or have hole-like structures.

At a side surface of the holder 64, a light source air inlet 64 b isdisposed for allowing an incoming flow of the air to cool down the lightsource 61. At a top surface of the holder 64, a light source air outlet64 c is disposed for allowing an outgoing flow of the air heated by thelight source 61.

The light source bracket 62 is provided with an airflow path 65 forallowing an incoming flow of the air taken from an air intake blower(see FIG. 22 and the like) as described later. A sectional shape of theairflow path 65 in which air flows is a rectangle or nearly rectangle.An end of the airflow path 65 is a wall. A thickness of walls of theairflow path 65 is constant or almost constant. Thereby, when viewedfrom a side which is not used as the airflow path 65, it is observed asa cuboid-like protrusion. As illustrated in FIG. 20, on a surface of thelight source bracket 62 opposite to another surface on which the lightsource 61 is held, nearly rectangular convex portion is formed along theshape of the airflow path 65. This convex portion can be used as ahandle portion 68 allowing for the user to pinch the handle portion 68by fingers to pull out the light source unit 60 for the replacementthereof. Therefore, the outer wall itself of the airflow path 65 is ashape of the handle portion 68. In order to use the airflow path 65 asthe handle portion, however, the outer wall itself of the airflow path65 does not need to be precisely the handle shape, and may have somemodification in its shape within an extent that the user can pinch it byfingers. At the air intake side (front side in the figure) of theairflow path 65, openings 65 a are disposed for guiding a part of theairflow flowing into the airflow path 65 to between the light sourceunit 60 and an access cover 54 (see FIG. 8) which will be describedlater. The cooling of the light source unit 60 will be described later.

A planar portion 64 d 2 on which the light source positioning protrusion64 a 3 is formed as illustrated in FIG. 4, and planar portions 64 d 1provided with the light source positioning holes 64 a 1 and 64 a 2 areabutting members for abutting against the lighting bracket when pressedby a pressing member of the access cover, as described later.

Next, the lighting unit 20 will be described.

FIG. 6 perspectively illustrates optical system components housed in thelighting unit 20, while also illustrating other units.

As illustrated in FIG. 6, the lighting unit 20 includes a color wheel21, a light tunnel 22, two relay lenses 23, a cylinder mirror 24, and aconcave mirror 25, which are held by the lighting bracket 26. Thelighting bracket 26 has a housing-like portion 261 in which two relaylenses 23, the cylinder mirror 24, and the concave mirror 25 are housed.Among four lateral sides of the housing-like portion 261, only rightlateral side in the figure has a wall. Other three lateral sides areopened. At the opening of the lateral side deep in X direction in thefigure, an OFF light board 27 (see FIG. 7) is attached. At the openingof the front lateral side in X direction in the figure, a covercomponent is attached. Thereby, two relay lenses 23, the cylinder mirror24, and the concave mirror 25, which are housed in the housing-likeportion 261 of the lighting bracket 26, are surrounded by the lightingbracket 26, the OFF light board 27 (see FIG. 7), and the covercomponent.

At a bottom side of the housing-like portion 261 of the lighting bracket26, a lighting through hole 26 d is formed for exposing the DMD 12.

The lighting bracket 26 has three legs 29. These legs 29 abut on a basecomponent 53 (see FIG. 20) of the projector 1 to support weights of thefirst optical unit 30 and the second optical unit 40 which are stackedand fixed on the lighting bracket 26. These legs 29 disposed as suchform a space for allowing an incoming flow of ambient air to a heat sink13 (see FIG. 7) as a cooling unit to cool down the DMD 12 of the imageforming unit 10, which will be described later.

Incidentally, in FIG. 6, reference numerals 32 a 3 and 32 a 4 refer tolegs of the lens holder 32 of the first optical unit 30, and a referencenumeral 45 a 3 refer to a screw fix portion 45 a 3 of the second opticalunit 40.

FIG. 7 is a perspective view from a direction indicated by an arrow A inFIG. 6 and illustrates the lighting unit 20, the projection lens unit31, and the image forming unit 10.

At an upper side of the housing-like portion 261 of the lighting bracket26, an upper plate 26 b is disposed orthogonally to Y direction in thefigure. At four corner of this upper plate 26 b, through holes forletting through screws for screwing the first optical unit 30 aredisposed (in FIG. 7, through holes 26 c 1 and 26 c 2 are illustrated).Positioning holes 26 e 1 and 26 e 2 for positioning the first opticalunit 30 to the lighting unit 20 are disposed adjacent to the throughholes 26 c 1 and 26 c 2 located at the front side in X direction in thefigure. Among two positioning holes disposed at the front side in Xdirection in the figure, the positioning hole 26 e 1 at a side of whichthe color wheel 21 is disposed is a main reference for the positioningand has a round hole shape. The positioning hole 26 e 2 at an oppositeside of the color wheel 21 installation side is a sub reference for thepositioning, and has an elongate hole extending in Z direction. Aperiphery of through hole 26 c 1 and a periphery of through hole 26 c 2are protruded from a surface of the upper plate 26 b of the lightingbracket 26. These protruded peripheries functions as positioningprotrusions 26 f for positioning the first optical unit 30 in Ydirection. If the positioning accuracy in Y direction should be improvedwithout employing the positioning protrusions 26 f, it is required toimprove an entire flatness of the upper plate 26 b of the lightingbracket 26. This raises the cost. On the other hand, by employing thepositioning protrusions 26 f, it is enough to improve the flatness ofthe positioning protrusions 26 f only. Thereby, the positioning accuracyin Y direction can be improved, while saving the cost.

A light shielding plate 262 is disposed at the opening of the upperplate 26 b of the lighting bracket 26. A lower portion of the projectionlens unit 31 engages with the light shielding plate 262, so that thelight from the upper side to inside of the housing-like portion 261 isshielded.

A space between the through hole 26 c 1 and the through hole 26 c 2 ofthe lighting bracket 26 is cut off so as not to be an obstacle when thesecond optical unit 40 is screwed to the first optical unit 30, whichwill be described later.

At the cooler wheel side (the front side in Z direction in the figure)of the lighting bracket 26, a cylinder-like light source positioningjoint portion 26 a 3 is disposed. The cylinder-like light sourcepositioning joint portion 26 a 3 has a vertical through hole into whichthe protrusion-like light source positioning portion 64 a 3 (see FIG. 4)formed on the upper surface of the holder 64 of the light source unit 60fits or engages. Below the light source positioning joint portion 26 a3, two protrusion-like light source positioning joint portions 26 a 1and 26 a 2 are disposed, which engage with two hole-like light sourcepositioning portion 64 a 1 and 64 a 2 formed on the light source bracket62 side of the holder 64. By engaging three light source positioningportions 64 a 1 to 64 a 3 of the holder 64 with three light sourcepositioning joint portions 26 a 1 to 26 a 3 formed on the lightningbracket 26 of the lighting unit 20, the light unit 60 is positioned andfixed to the lighting unit (see FIG. 3).

To the lighting bracket 26, a lighting cover 28 for covering the colorwheel 21 and the light tunnel 22 is attached.

FIG. 8 is for explaining the light path L of the light in the lightingunit 20.

The color wheel 21 has a disc-like shape, and is fixed to a motor shaftof a color motor 21 a. The color wheel 21 is provided with filters suchas red (R) filer, green (G) filter, and blue (B) filter in a rotatingdirection. The light collected by the reflector disposed on the holder64 of the light source unit 60 reaches a peripheral portion of the colorwheel 21 through the emitting window 63. The light reached theperipheral portion of the color wheel 21 is split into R, G and B in atime divided manner by the rotation of the color wheel 21.

The light split by the color wheel 21 enters the light tunnel. 22. Thelight tunnel 22 has a square cylinder shape. The inner peripheralsurface of the light tunnel 22 is a mirror surface. The light enteredthe light tunnel 22 is formed into a uniform surface light source whilereflected multiple times on the inner surface of the light tunnel 22,and emitted to the relay lenses 23.

The light passed through the light tunnel 22 transmits two relay lenses23, and is reflected by the cylinder mirror 24 and the concave mirror25, and is collected on an image forming surface of the DMD 12 where animage is formed.

Next, the image forming unit 10 will be described.

FIG. 9 perspectively illustrates the image forming unit 10.

As illustrated in FIG. 9, the image forming unit 10 is provided with aDMD board 11 to which the DMD 12 is attached. The DMD 12 is attached toa socket 11 a formed on the DMD board 11 so that the image formingsurface in which micromirrors are arranged in an array (grid) facesupward. The DMD board 11 is provided with a drive circuit and the likefor driving the DMD mirror. A heat sink 13 as a cooling unit to cooldown the DMD 12 is fixed to a back side (an opposite side of the socket11 a formed side) of the DMD board 1. A portion of the DMD board 11 towhich the DMD 12 is attached is opened through. The heat sink 13 isprovided with a protrusion portion 13 a (see FIG. 8) which engages withthe through hole of the DMD board 11. A leading head of the protrusionportion 13 a is flattened. This protrusion portion 13 a is inserted intothe through hole of the DMD board 11, so that the flat portion at theleading edge of the protrusion portion 13 a abuts on the back surface(the opposite surface of the image forming surface) of the DMD 12. It ispossible to improve the adhesiveness and thermal conductivity betweenthe flat portion of the protrusion portion 13 a and the back surface ofthe DMD 12 by applying an elastically deformable heat transfer sheet tothe flat portion and/or a portion of the back surface of the DMD 12 onwhich the heat sink 13 abuts.

By a fix unit 14, the heat sink 13 is pressured and fixed to the DMDboard 11 at a side opposite to a side which the socket 11 a is formed.The fix unit 14 includes plate-like fix portions 14 a. One of theplate-like portions 14 a faces the back surface of the DMD board 11 at aright side in the figure. The other plate-like portion 14 a faces theback surface of the DMD board 11 at a left side in the figure. Pressureportions 14 b are disposed near both ends in X direction of each fixportion 14 a so that right and left fix portions 14 a are connected.

The heat sink 13 is pressured and fixed by the fix unit 14 to the DMDboard 11 at a side opposite to a side which the socket 11 a is formed,when the image forming unit 10 is screwed to the lighting bracket 26(see FIG. 7).

Now, the fix procedure of the image forming unit 10 to the lightingbracket 26 will be described. First, the image forming unit 10 ispositioned to the lighting bracket 26 so that the DMD 12 faces theopening of the lighting through hole 26 d formed at the lower surface ofthe lighting bracket 26 of the lighting unit 20 as illustrated in FIG.6. Next, a screw is inserted from the lower side so that the screw goesthrough the through hole of the fix portion 14 a and the through hole ofthe DMD board 11. The screw is screwed into a screw hole formed at thelower side of the screw portion 262 (see FIG. 3) formed on the lightingbracket 26. As the screw is screwed into the screw portion 262 of thelighting bracket 26, the pressure portion 14 b presses the heat sink 13toward the DMD board 11. Thereby, the heat sink 13 is pressed and fixedby the fix unit 14 to a surface of the DMD board 11 opposite to asurface on which the socket 11 a is formed.

Thus, the image forming unit 10 is fixed to the lighting unit 26. Asillustrated in FIG. 6, three legs 29 also support the weight of theimage forming unit 10.

In the image forming surface of the DMD 12, a plurality of movablemicromirrors are arranged in an array (grid). Each of micromirrors cantilt its mirror surface by a predetermined angle around a torsion axis.Thus, each of micromirrors can take ON position or OFF position. If amicromirror is at ON position, the light from the light source 61 isreflected to the first optical system 70 (see FIG. 2), as illustrated byan arrow L2 in FIG. 8. If a micromirror is at OFF position, the lightfrom the light source 61 is reflected to the OFF light plate 27 (see anarrow L1 in FIG. 8) held at the lateral side of the lighting bracket 26as illustrated in FIG. 7. Therefore, by driving each mirrorindependently, it is possible to control the light projection for eachpixel of the image data and thus form the image.

The light reflected to the OFF light plate 27 is absorbed as heat andthen cooled by an ambient air flow.

Next, the first optical unit 30 will be described.

FIG. 10 perspectively illustrates the first optical unit 30 with thelighting unit 20 and the image forming unit 10.

As illustrated in FIG. 10, the first optical unit 30 is disposed abovethe lighting unit 20. The first optical unit 30 is provided with theprojection lens unit 31 holding the first optical system 70 (see FIG. 2)including a plurality of lenses, and the lens holder 32 for holding thisprojection lens unit 31.

The lens holder 32 has four legs 32 a 1 to 32 a 4 extending downward (inFIG. 10, only legs 32 a 2 and 32 a 3 are illustrated. The leg 32 a 1 isillustrated in FIG. 3, and the leg 32 a 4 is illustrated in FIG. 6). Ascrew hole is formed at a bottom surface of each of legs 32 a 1 to 32 a4, for screwing each leg is screwed to the lighting bracket 26.

The projection lens unit 31 is provided with a focus gear 36 with whichan idle gear 35 engages. The idle gear 35 engages with a lever gear 34.A focus lever 33 is fixed to a rotational axis of the lever gear 34. Theleading edge of the focus lever 33 is exposed from the main body asillustrated in FIG. 1.

When the focus lever 33 is moved, the focus gear 36 is rotated via thelever gear 34 and the idle gear 35. When the focus gear 36 is rotated,the plurality of lenses composing the first optical system 70 in theprojection lens unit 31 is moved to predetermined directions so that afocus of the projection image is adjusted.

The lens holder 32 has four screw through holes 32 c 1 to 32 c 4 throughwhich screws 48 penetrate for screwing the second optical unit 40 to thefirst optical unit 30 (in FIG. 10, three screw through holes 32 c 1 to32 c 3 are illustrated. Each of three screw through holes is illustratedin a state that a screw 48 is penetrated. The edge of the screw 48 isviewed in the figure.) Around each of screw through holes 32 c 1 to 32 c4, the second optical unit positioning protrusions 32 d 1 to 32 d 4protruded from the surface of the lens holder 32 are formed (in FIG. 10,32 d 1 to 32 d 3 are illustrated).

FIG. 11 is a sectional view along A-A line in FIG. 10.

As illustrated in FIG. 11, legs 32 a 1 and 32 a 2 are provided withpositioning joint protrusions 32 b 1 and 32 b 2, respectively. Thepositioning joint protrusion 32 b 1 at the right side in the figure isinserted into the round hole shaped positioning hole 26 e 1 which isformed as the main reference at the upper plate 26 b of the lightingbracket 26. The positioning joint protrusion 32 b 2 at the left side inthe figure is inserted into the elongate hole shaped positioning hole 26e 2 which is formed as the sub reference on the upper plate 26 b of thelighting bracket 26. Thus, the positioning in Z direction and Xdirection is done. Screws 37 are inserted into through holes 26 c 1 to26 c 4 formed at the upper plate 26 b of the lighting bracket 26, sothat screws 37 are screwed into screw holes formed on each of legs 32 a1 to 32 a 4 of the lens holder 32, and the first optical unit 70 ispositioned and fixed to the lighting unit 20.

The upper portion of the projection lens unit 31 above the lens holder32 is covered by a mirror holder 45 (see FIG. 13) of the second opticalunit, which will be described later. As illustrated in FIG. 3, below thelens holder 32 of the projection lens unit 31, a portion of theprojection lens unit 31 between the lens holder 32 and the upper plate26 b of the lighting bracket 26 of the lighting unit 20 is exposed.However, the light cannot enter from this exposed portion to the lightpath of the image, since the projection lens unit 31 engages with thelens holder 32.

Next, the second optical unit 40 will be described.

FIG. 12 perspectively illustrates the second optical system included inthe second optical unit 49, while also illustrating the projection lensunit 31, the lighting unit 20 and the image forming unit 10.

As illustrated in FIG. 12, the second optical unit 40 is provided withthe reflecting mirror 41 composing the second optical system, and theconcavely curved mirror 42. A reflecting surface of the curved mirror 42may be a spherical surface, a rotationally symmetric aspheric surface, afree curved surface or the like.

FIG. 13 perspectively illustrates the second optical unit 40 with thefirst optical unit 30, the lighting unit 20, and the image forming unit10.

As illustrated in FIG. 13, the second optical unit 40 is provided with atransmissive glass 51 for transmitting the light image reflected fromthe curved mirror 42 and for protecting optical components in the unitfrom dust.

The second optical unit 40 includes a mirror bracket 43 for holding thereflecting mirror 41 and the transmissive glass 51, a free mirrorbracket 44 for holding the curved mirror 42, and the mirror holder 45 towhich the mirror bracket 43 and the free mirror bracket 44 are attached.

The mirror holder 45 has a box shape. Specifically, it has a U shapewhen viewed from the upper side in which the upper side, the bottomside, and the depth side of X direction in the figure of the box areopened. Edge portions of the upper opening of the mirror holder 45extend from the front side to the depth side in X direction at the frontside and the depth side in Z direction. Each of these edge portions hasan inclined portion and a parallel portion. The inclined portioninclines so that it is raised as it goes to the depth in X direction inthe figure. The parallel portion is parallel to X direction in thefigure. The inclined portion is on the front side of the parallelportion in X direction. An edge portion of the upper opening of themirror holder 45 extending in Z direction at the front side in Xdirection in the figure is parallel to Z direction in the figure.

The mirror bracket 43 is attached to the upper part of the mirror holder45. The mirror bracket 43 has an inclined surface 43 a and a parallelsurface 43 b. The inclined surface 43 a abuts on the inclined portion ofthe upper opening edges of the mirror holder 35, and inclines so that itis raised as it goes to the depth in X direction in the figure. Theparallel surface 43 b, which is parallel to X direction, abuts on theparallel portion of the upper opening edges of the mirror holder 45. Theinclined surface 43 a and the parallel surface 43 b have openings,respectively. In these openings, the reflecting mirror 41 is held sothat the opening of the inclined surface 43 a is closed, and thetransmissive glass 51 is held so that the opening of the parallelsurface 43 b is closed.

The reflecting mirror 41 is positioned and fixed to the inclined surface43 a of the mirror bracket 43 by pressing Z direction both ends of thereflecting mirror 41 against the inclined surface 43 a of the mirrorbracket 43 by a flat spring-like mirror pressing members 46. One Zdirection end of the reflecting mirror 41 is fixed by two mirrorpressing members 46, and the other Z direction end of the reflectingmirror 41 is fixed by one mirror pressing member 46.

The transmissive glass 51 is positioned and fixed to the mirror bracket43 by pressing Z direction both ends of the transmissive glass 51against the parallel surface 43 b of the mirror bracket 43 by a flatspring-like glass pressing members 47. Each Z direction end of thetransmissive glass 51 is fixed by one glass pressing member 47,respectively.

The free mirror bracket 44 for holding the curved mirror 42 has arms 44a at Z direction both sides thereof. Each of arms 44 a declines so thatit is lowered as it goes to the front side from the depth side in Xdirection in the figure. The free mirror bracket 44 also has aconnecting portion 44 b for connecting two arms 44 a at an upper side oftwo arms 44 a. With regard to this free mirror bracket 44, arms 44 a areattached to the mirror holder 45 so that the curved mirror 42 covers theX direction depth side opening of the mirror holder 45.

The curved mirror 42 is fixed in such a manner that a substantialcentral portion of the transmissive glass side end of the curved mirror42 is pressed against the connecting portion 44 b of the free mirrorbracket 44 by a plate spring-like free mirror pressing member 49, and Zdirection both ends of the curved mirror 42 on the first optical systemside are fixed to arms 44 a of the free mirror bracket 44 by screws.

The second optical unit 40 is stacked on and fixed to the lens holder 32of the first optical unit 30. Specifically, an under surface 451 isformed under the mirror holder 45 which faces the upper surface of thelens holder 32. The under surface 451 has four cylindrical screw joints45 a 1 to 45 a 4 (only 45 a 1 and 45 a 2 are illustrated in FIGS. 13,and 45 a 3 is illustrated in FIG. 6) formed for screwing the secondoptical unit 40 to the first optical unit 30. The second optical unit 40is fixed to the first optical unit 30 in such a manner that screws 48are penetrated through screw holes 32 c 1 to 32 c 4 formed on the lensholder 32 of the first optical unit 30, and then screwed and fastenedinto screw joints 45 a 1 to 45 a 4. At this time, the under surface ofthe mirror holder 45 of the second optical unit 40 abuts on the secondoptical unit positioning protrusions 32 d 1 to 32 d 4 of the lens holder32, so that the second optical unit 40 is positioned in Y direction andfixed.

When the second optical unit 40 is stacked on and fixed to the lensholder 32 of the first optical unit 30, the upper portion of theprojection lens unit 31 above the lens holder 32 as illustrated in FIG.10 is housed in the mirror holder 45 of the second optical unit 40. Whenthe second optical unit 40 is stacked on and fixed to the lens holder 32of the first optical unit 30, a gap is made between the curved mirror 42and the lens holder 32. The idle gear 35 (see FIG. 10) is inserted intothe gap.

FIG. 14 perspectively illustrates the light paths from the first opticalsystem 70 to the projection plane 101 (screen).

The light beam passed through the projection lens unit 31 composing thefirst optical system 70 forms an intermediate image conjugate to theimage formed on the DMD 12 between the reflecting mirror 41 and thecurved mirror 42. This intermediate image is formed as a curved mirrorimage between the reflecting mirror 41 and the curved mirror 42. Next,the diverging light after forming the intermediate image enters theconcavely curved mirror 42 to become a convergent light. By thisconvergent light through the curved mirror 42, the intermediate imagebecomes a “further enlarged image” to be projected and formed on theprojection plane 101.

Thus, owing to the structure in which the projection optical system iscomposed of the first optical system 70 and the second optical system,the intermediate image is formed between the first optical system 70 andthe curved mirror 42 of the second optical system, and the intermediateimage is enlarged and projected by the curved mirror 42, the projectiondistance can be shortened. Thus, the projectors can be used in smallrooms.

As illustrated in FIG. 14, the first optical unit 30 and the secondoptical unit 40 are stacked on and fixed to the lighting bracket 26.Furthermore, the image forming unit 10 is also fixed. Therefore, legs 29of the lighting bracket 26 are fixed to the base component 53 so thatthe legs 29 support weights of the first optical unit 30, the secondoptical unit 40 and the image forming unit 10.

FIG. 15 schematically illustrates an arrangement of units in theprojector.

As illustrated in FIG. 15, the image forming unit 10, the lighting unit20, the first optical unit 30 and the second optical unit 40 arearranged in a stacked manner in Y direction which is a short axisdirection of the projection plane. Relative to stacked units of theimage forming unit 10, the lighting unit 20, the first optical unit 30and the second optical unit 40, the light source unit 60 is disposed inZ direction which is a long axis direction of the projection plane.Thus, in the present embodiment, the image forming unit 10, the lightingunit 20, the first optical unit 30, the second optical unit 40 and thelight source unit 60 are arranged in Y direction or Z direction whichare parallel to the projection plane 101. More specifically, the imageforming unit 10 and the lighting unit 20 form the image forming part A,while the first optical unit 30 and the second optical unit 40 form theprojection optical part B. The image forming part A, the projectionoptical part B, and the light source unit 60 are arranged so that alight emitting surface of the light source unit 60 intersects a surfaceof the stacked body of the image forming part A and the projectionoptical system B which is parallel to the projection image and theprojection plane 101. The image forming part A and the light source unit60 are arranged along the same line parallel to the base component 53.The image forming part A and the projection optical part B are arrangedalong the same line perpendicular to the base component 53, in the orderof the image forming part A and the projection optical part B from thebase component 53.

In the present embodiment, above the light source unit 60, a powersource unit 80 is stacked for supplying an electrical power to the lightsource 61 and the DMD 12. The light source unit 60, the power sourceunit 80, the image forming part A and the projection optical part B arehoused in a case of the projector 1 made of an outer cover (see FIG.20), which will be described later, covering the upper surface of theprojector, the base component 53 and the surrounding of the projector 1.

FIG. 16 illustrates an example of usage of the projector 1 according tothe present embodiment. FIG. 17 illustrates an example of usage of aconventional projector 1A. FIG. 18 illustrates an example of usage of aprojector 1B in which a light source 61 and a lighting unit 20 arearranged in a direction orthogonal to a projection plane 101.

As illustrated in FIG. 16 to FIG. 18, the projector 1 is used in such amanner that the projector 1 is put on a table 100 and an image isprojected on the projection plane 101 such as a white board, when usedin a meeting room or the like for example.

As illustrated in FIG. 17, in the conventional projector 1A, a DMD 12(image forming element), a lighting unit 20, a first optical system 70,and a second optical system (concave mirror 42) are arranged in seriesin a direction orthogonal to a plane of a projection image projected ona projection plane 101. Therefore, the projector 1A is elongated in thedirection (X direction) orthogonal to the projection plane of theprojector 1A. Thus, the projector 1A occupies a space in the directionorthogonal to the projection plane 101. Desks and chairs used by viewersof the image projected on the projection screen 101 are generallyarranged in the direction orthogonal to the projection plane. Thus, ifthe projector occupies the space in the direction orthogonal to theprojection plane, the layout space allowed for desks and chairs islimited. It is inconvenient.

In the projector 1B illustrated in FIG. 18, a DMD 12 (image formingelement), a lighting unit 20 and a first optical system 70 are arrangedin series parallel to a plane of a projection image projected on aprojection plane 101. Therefore, in comparison with the projector 1Aillustrated in FIG. 17, a length in a direction orthogonal to theprojection plane 101 can be shortened. However, in the projector 1Billustrated in FIG. 18, relative to the lighting unit 20, a light source61 is arranged in the direction orthogonal to the plane of theprojection image. Therefore, the length in the direction orthogonal tothe projection plane 101 of the projector cannot be sufficientlyshortened.

On the other hand, in the projector 1 according to the presentembodiment illustrated in FIG. 16, the image forming part A composed ofthe image forming unit 10 and the lighting unit 20 and the projectionoptical part B composed of the first optical unit 30 and the reflectingmirror 41 are arranged in series along Y direction in the figure amongdirections parallel to the projection plane 101 and the image plane ofthe projection image projected on the projection plane 101. Furthermore,the light source unit 60 and the lighting unit 20 are arranged in seriesalong Z direction in the figure among directions parallel to the planeof the projection image projected on the projection plane 101. Namely,the projector 1 according to the present embodiment has a configurationin which the light source unit 60, the image forming unit 10, thelighting unit 20, the first optical unit 30, and the reflecting mirror41 are arranged in directions (Z and Y directions in the figure)parallel to the plane of the projection image projected on theprojection plane 101. Each of the light source unit 60, the imageforming unit 10, the lighting unit 20, the first optical unit 30, andthe reflecting mirror 41 is arranged parallel to the projection planeand the image plane of the projection image. Thus, since the lightsource unit 60, the image forming unit 10, the lighting unit 20, thefirst optical unit 30, and the reflecting mirror 41 are arranged indirections (Z and Y directions in the figure) parallel to the plane ofthe projection image projected on the projection plane 101, a length ina direction (X direction in the figure) orthogonal to the projectionplane 101 can be shortened as illustrated in FIG. 16, in comparison withprojectors illustrated in FIG. 17 and FIG. 18. Thereby, the projector 1cannot be an obstacle for the layout of desks and chairs in view ofspaces. Thus, it is possible to provide the convenient projector 1.

In the present embodiment, as illustrated in FIG. 15, above the lightsource unit 60, the power source unit 80 for supplying the electricpower to the light source 61 and the DMD 12 are disposed in a stackedmanner. Thereby, a length of the projected 1 in Z direction isshortened.

FIG. 19 illustrates another example of usage of the projector 1according to the present embodiment.

As illustrated in FIG. 19, the projector 1 according to the presentembodiment can be used by hanging from a ceiling 105. Also in this case,the length of the projector 1 in the direction orthogonal to theprojection plane 101 is short. Therefore, when the projector 1 isinstalled at the ceiling 105, the projector 1 can be installed withoutaffecting a lighting equipment 106 disposed on the ceiling 105.

In the present embodiment, the second optical system is composed of thereflecting mirror 41 and the curved mirror 42. However, the secondoptical system may be composed only of the curved mirror 42. Thereflecting mirror may be a flat mirror, a mirror having a positiverefractive power, or a mirror having a negative refractive power. In thepresent embodiment, the concave mirror is used as the curved mirror 42.However, a convex mirror may be used. In this case, the first opticalsystem 70 is configured so that an intermediate image is not formedbetween the first optical system 70 and the curved mirror 42.

The light source 61 is to be replaced periodically, since its life timeends after use over time. For this purpose, in the present embodiment,the light source unit 60 is arranged detachably from and attachably tothe main body.

FIG. 20 perspectively illustrates an installation side of the projector1.

As illustrated in FIG. 20, the base component 53 constituting the bottomsurface of the projector 1 is provided with an access cover 54(openable/closeable cover). The access cover 54 is provided with arotating operating member 54 a. The rotating operating member 54 a canbe rotated to release the lock between the access cover 54 and the mainbody, so that the access cover can be removed from the main body.Electrical power air inlets 56 are disposed adjacent in X direction tothe access cover 54 of the base component 53.

As illustrated in FIG. 20, in one of XY planes of an outer cover 59 ofthe projector 1, an air inlet 84, and an external input portion 88 fromwhich the image data or the like is input from an external device suchas a PC are disposed.

FIG. 21 perspectively illustrates a state that the access cover 54 isremoved from the main body.

As illustrated in FIG. 21, if the access cover 54 is removed, a side ofthe light source bracket 62 opposite to a side on which the light source61 is mounted in the light source unit 60 is exposed. The airflow path65 formed so as to cubically protrude toward the access cover 54 is usedas the handle portion 68 allowing for the user to pinch it by fingersfor the replacement of the light source unit 60.

When the light source unit 60 is to be removed from the main body, thehandle portion 68 or a finger grip 66 is pinched and pulled toward thenearer side in the figure, so that the light source unit 60 is removedfrom the opening of the main body. When the light source unit 60 is tobe mounted to the main body, the light source unit 60 is inserted fromthe opening of the main body. As the light source unit 60 is insertedinto the main body, the connecting portion 62 a as illustrated in FIG. 4connects with the power source side connector of the main body. Threelight source positioning portions 64 a 1 to 64 a 3 of the holder 64 asillustrated in FIG. 4 engage with three light source positioning jointportions 26 a 1 to 26 a 3 formed on the lighting bracket 26 of thelighting unit 20 as illustrated in FIG. 7, so that the light source unit60 is positioned to the main body. Thus, the mounting of the lightsource unit 60 is completed. Then, the access cover 54 is attached tothe base component 53.

The base component 53 has three legs 55. By rotating these legs 55, theprotruded extent of legs 55 from the base component 53 can be changed,and the adjustment in the height direction (Y direction) can be done.

As illustrated in FIG. 21, in the other XY plane of the outer cover 59,an exhaust outlet 85 is disposed.

FIG. 22 is a view illustrating air flows in the projector 1 according tothe present embodiment. In FIG. 22, the projector 1 is viewed from thedirection (X direction) orthogonal to the projection plane 101. In FIG.23, schematically illustrated components in FIG. 22 are specificallyillustrated carrying the same reference numerals. In FIG. 22 and FIG.23, arrows indicate directions to which air flows. FIG. 24 is a crosssection along A-A line of FIG. 23. FIG. 25 is a cross section along B-Bline of FIG. 23.

As illustrated in FIG. 22, at one side (left side in the figure) of theprojector 1, the air inlet 84 is formed for taking an ambient air intothe projector 1. At another side (right side in the figure) of theprojector 1, the exhaust outlet 85 is formed for discharging the airinside of the projector 1. An exhaust fan 86 is disposed so as to facethe exhaust outlet 86.

The exhaust outlet 85 and a part of the air inlet 84 are located at alevel between the light source unit 60 and the operating part 83, whenthe projector 1 is viewed from the direction (X direction) orthogonal tothe projection plane 101. Thereby, the ambient air taken from the airinlet 84 flows to ZY plane of the mirror holder 45 and the back side ofthe curved mirror 42 of the second optical unit 40 as illustrated inFIG. 12. Along the mirror holder 45 and the back side of the curvedmirror 42, the air flows toward the exhaust outlet 85. The power sourceunit 80 disposed above the light source unit 60 has an arch-like shapewhen viewed from Z direction in the figure. The air moved along themirror holder 45 and the back side of the curved mirror 42 toward theexhaust outlet 84 flows into a space surrounded by the power source unit80 and is then discharged from the exhaust outlet 85.

Thus, the exhaust outlet and the part of the air inlet are located at alevel between the light source unit 60 and the operating part 83 whenthe projector 1 is viewed from the direction (X direction) orthogonal tothe projection plane 101. Thereby, there is generated the airflow whichflows between the light source unit 60 and the operating part 83 and isthen discharged from the exhaust outlet 85.

A light source blower 95 is disposed at a position allowing forsuctioning the air around the color motor 21 a (see FIG. 6) to drive androtate the color wheel 21 of the lighting unit 20. Thereby, the colormotor 21 a can be cooled by the airflow generated by the air suction ofthe light source blower 95.

The air suctioned by the light source blower 95 flows to the lightsource air inlet 64 b (see FIG. 4) of the holder 64 through the lightsource duct 96. A part of the air flows into the light source duct 96flows from an opening 96 a, which is formed on the light source duct 96on a side facing the outer cover 59 (see FIG. 20), to between the lightsource housing 97 and the outer cover 59.

The air flowing from the opening 96 a of the light source duct 96 tobetween the light source housing 97 and the outer cover 59 cools downthe light source housing 97 and the outer cover 59, and is thendischarged from the exhaust outlet 85 by the exhaust fan 86.

The air flowing to the light source air inlet 64 b flows into the lightsource 61. After cooling the light source 61, the air is discharged fromthe light source air outlet 64 c formed on the upper surface of theholder 64. The air discharged from the light source air outlet 64 cflows into the space surrounded by the power source unit 80 from theopening on the upper surface of the light source housing 97. Then, theair is mixed with the low temperature air which flows along the outsideof the second optical unit 40 and flows into the space surrounded by thepower source unit 80. Then, the air is discharged from the exhaustoutlet 85 by the exhaust fan 86. Thus, the high temperature airdischarged from the light source air outlet 64 c is mixed with theambient air and then discharged to the ambient. Thereby, it is possibleto prevent the temperature rise of the air discharged from the exhaustoutlet 85.

The operating part 83 operated by the user is preferably formed on theupper surface of the apparatus for the easy operation by the user. Inthe present embodiment, however, since the transmissive glass 51 isdisposed on the upper surface of the projector 1 for the purpose ofprojecting the image on the projection plane 101, the operating part 83needs to be disposed above the light source 61 as if they overlap eachother when the projector 1 is viewed from the Y direction.

In the present embodiment, the high temperature air after cooling thelight source 61 is guided to the exhaust outlet 85 by the airflow fromthe air inlet 84 to the exhaust outlet 85 between the light source unit60 and the operating part 83. This high temperature air is preventedfrom flowing to the operating part 83. Thereby, the operating part 83 isprevented from being heated by the high temperature air after coolingthe light source 61. Furthermore, a part of the air which flows from theair inlet 84 to the exhaust outlet 85 through the outside of the secondoptical unit 40 cools the operating part 83 by flowing beneath theoperating part 83. This also contributes to the prevention of thetemperature raise of the operating part 83.

Owing to the air suction of the exhaust fan 86, the ambient air issuctioned from the power source air inlets 56 formed on the basecomponent 53 as illustrated in FIG. 20. At the X direction depth side inthe figure beyond the light source housing 97, a ballast board 3 a (seeFIG. 24 and FIG. 25) for supplying a stable electric power (electriccurrent) to the light source 61 is disposed. The ambient air suctionedfrom the power source air inlets 56 moves upward through between thelight source housing 97 and the ballast board. While this movement, theair cools the ballast board. Then, the air flows into the spacesurrounded by the power source unit 80 disposed above the ballast board.Then, the air is discharged from the exhaust outlet 85 by the exhaustfan 86.

At the lower left side of the main body in the figure, a cooling unit120 is disposed for cooling the heat sink 13 of the image forming unit10 and the light source bracket 62 of the light source unit 60. Thecooling unit 120 is provided with an air intake blower 91, a verticalduct 92, and a horizontal duct 93.

Referring to FIG. 27 also, airflow from the air intake blower 91 will beexplained. The air intake blower 91 is disposed facing the air inlet 84at the lower part of the inlet 84. The ambient air is taken from oneside of the blower 91 facing the air inlet 84 through the air inlet 84.The air inside of the apparatus is taken from the other side of theblower 91 which is opposite to the one side facing the air inlet 84. Thetaken air is directed to the vertical duct 92 disposed under the blower91. The air directed to the vertical duct 92 moves downward and is thendirected to the horizontal duct 93 connected to the vertical duct 92 atthe lower part of the duct 92.

In the horizontal duct 93, there is a heat sink 13 attached to the backside of the image forming surface of the DMD 12. The heat sink 13 iscooled by the air flowing in the horizontal duct 93. By cooling the heatsink 13, the DMD 12 can be cooled effectively. Thus, the DMD 12 can beprevented from being heated to high temperature.

The air moved through the horizontal duct 93 flows in the airflow path65 or the openings 65 a formed in the light source bracket 62 of thelight source unit 60 as illustrated in FIG. 4. The air entered theopenings 65 a flows to between the access cover 54 and the light sourcebracket 62, so that the access cover 54 is cooled.

On the other hand, the air entered the airflow path 65 cools the lightsource bracket 62 and then flows to a part of the light source 61opposite to the emitting side of the light source 61, so that a part ofthe light source 61 opposite to the reflecting surface of the reflector67 is cooled. Therefore, the air flowing through the air flow path 65takes heat from both the light source bracket 62 and the light source61. The air passed around the reflector 67 flows through an exhaust duct94 which directs the air from a level (height) of the light sourcebracket 62 to a level around the lower portion of the exhaust fan 86.Then, the air combines with the air discharged from the light source airoutlet 64 c, and flows to the exhaust outlet 85 through a fluid guide87. The air is discharged from the exhaust outlet 85 by the exhaust fan86. On the other hand, the air which flows between the access cover 54and the light source bracket 62 through the openings 65 a moves insideof the apparatus after cooling the access cover 54, so that the air isdischarged from the exhaust outlet 85 by the exhaust fan 86.

FIG. 26 perspectively illustrates the cooling unit 120 with the lightingunit 20 and the light source unit 60. The layout of the cooling unit,the lighting unit 20, and the light source unit 60 is illustrated inFIG. 26.

As understood from FIG. 26, a space allowing for the installation of thehorizontal duct 93 under the lighting unit 20 is ensured by legs 29which support weights of the image forming unit 10, the lighting unit20, the first optical unit 30, and the second optical unit 40.

FIG. 27 is a longitudinal section view of FIG. 26. An arrow indicatesairflow from the air intake blower 91 to the vicinity of the reflector67 through the airflow path 65. The air flowing from the air intakeblower 91 flows as indicated by arrows K0, K1, and K3. The light sourceunit 60 is attached to the projector 1 so that the light source bracket62 and the airflow path 65 face the base component 53. Thereby, a flowpath for cooling the reflector 67 of the light source 61 and thehorizontal duct 93 as a flow path for cooling the heat sink 13 are alsodisposed on the base component 53. Consequently, a width of theprojector 1 in a direction orthogonal to the projection plane can beshortened.

FIG. 28 perspectively illustrates the horizontal duct 93 and the lightsource bracket 62 on the base component 53.

As illustrated in FIG. 28, the horizontal duct 93 is fixed to the basecomponent 53 of the projector 1. The horizontal duct 93 has an openingat a part of the upper surface thereof. The image forming unit 10 ismounted on the horizontal duct 93, so that the heat sink 13 of the imageforming unit 10 is inserted in this opening.

FIG. 29 illustrates airflow from the horizontal duct 93 to the lightsource bracket 62 when viewed from the under side of the base component53. FIG. 30 illustrates airflow from the horizontal duct 93 to the lightsource bracket 62 when viewed from the upper side of the base component53.

As illustrated in FIG. 29 and FIG. 30, the air from the horizontal duct93 flows into the airflow path 65 or openings 65 a formed in the lightsource bracket 62 of the light source unit 60. The air entered theopenings 65 a flows to between the access cover 54 and the light sourcebracket 62, so that the access cover 54 is cooled. Therefore, it ispossible to take heat from the access cover 54. With regard to theairflow path 65 itself, heat is taken from both the light source 61 sidethereof and the access cover 54 side thereof.

In the present embodiment, a halogen lamp, a metal halide lamp, a highpressure mercury lamp or the like may be used as the light source 61.Thereby, the light source 61 becomes high temperature when emittinglight. The light source bracket 62 and the access cover 54 become alsohigh temperature due to heat conductance and heat radiation from thelight source 61. When the light source unit 60 is replaced at the end ofthe lifetime, the access cover 54 and the light source bracket 62 aregrabbed or pinched by the user. Therefore, unless the access cover 54and the light source bracket 62 are cooled, the light source unit 60cannot be replaced. It is inconvenient. In the present embodiment,however, the airflow path 65 is disposed in the light source bracket 62as an airflow path formed in the handle portion 68 having an outer shapeallowing for the user to pinch it when removing the light source unit60, in order to cool the light source bracket 62 by passing the airthrough the path 65, and to cool the access cover 54 by passing the airbetween the access cover 54 and the light source bracket 62, asmentioned above. Thereby, the access cover 54 and the light sourcebracket 62 can be prevented form being heated to high temperature.Thereby, after the apparatus is stopped, the access cover 54 and thelight source bracket 62 can be quickly cooled down to a temperature atwhich the user can grab or pinch the cover 54 or the bracket 62.Therefore, in a case that the light source unit 60 needs to be replacedwhen the lifetime of the light source 61 ends during the operation ofthe apparatus, the user can grab or pinch the access cover 54 and/or thehandle portion (airflow path 65) of the light source unit 60 at earlystage. Therefore, the light source unit 60 can be replaced with a newone at an earlier stage than the replacement in the conventionalprojectors. Consequently, the downtime of the apparatus can beshortened.

As mentioned above, the airflow path 65 is a part into which the airflows and which is cooled intensively. Thus, the airflow path 65 is apart the temperature of which is suppressed to low level in the lightsource bracket 62. Therefore, owing to the configuration in which theairflow path 65 can be used as the handle portion, the light source unit60 can be replaced with a new one at an earlier stage. Consequently, thedowntime of the apparatus can be further shortened.

In the present embodiment, as mentioned above, the light source bracket62 is provided with the airflow path 65, so that the light sourcebracket 62 is cooled and thereby the temperature rise of the lightsource 61 is suppressed. Thereby, even if the amount of the air whichflows into the light source 61 is decreased in comparison with theconventional amount, the light source 61 can be cooled well. Thereby, itis possible to reduce the rotation speed (rpm) of the light sourceblower 95. Thus, a wind noise (kazekirion) of the light source blower 95can be reduced. Thereby, the noise of the apparatus can be reduced.Furthermore, since the rotation speed (rpm) of the light source blower95 can be reduced, the electrical power for the apparatus can be saved.Furthermore, it is possible to use a small light source blower 95generating a small amount of airflow. Thus, the apparatus can bedownsized.

The above explanations are only examples. The present invention hasspecific effects for each of the following aspects (1) to (5) includingembodiments.

(1)

An image projection apparatus includes a light source 61, a holdingmember 62 configured to hold the light source, and a blower. An image isformed by using light from the light source. A projection image of theformed image is formed by the apparatus. The holding member 62 includesa handle portion 68, and the handle portion 68 includes a first flowpath 65 for flowing air sent from the blower.

According to the configuration as such, as mentioned in embodiments, thetemperature rise of the handle portion 68 due to heat conductance andheat radiation from the light source 61 can be suppressed. Therefore, itis possible to reduce a time period from when the light source 61 isstopped until when the temperature of the handle portion 68 is solowered that the user can grab or pinch it. Thereby, it is possible toremove the light source unit 60 from the light source unit replacementopening 53 c of the main body, at an earlier stage from when the lightsource 61 stops due to its end of lifetime. Consequently, the downtimeof the apparatus can be shortened, since the light source unit 60 can bereplaced at an earlier stage from when the light source 61 stops due toits end of lifetime.

(2)

In the image projection apparatus described in (1), air after coolingthe handle portion 68 flows to the light source 61.

According to the configuration as such, as mentioned in embodiments, thetemperature rise of the light source 61 can be suppressed. Thereby, itis possible to reduce an amount of air from the light source blower 95as a blower to flow the air to the light source 61. Thus, the rotationspeed of the light source blower 95 can be reduced. Thereby, the windnoise of the light source blower 95 can be reduced. Thus, the noise ofthe apparatus can be reduced. Furthermore, the electric energyconsumption of the light source blower 95 can be reduced. Thus, theenergy saving apparatus can be provided. Furthermore, it is possible touse a small blower or fan generating a small amount of air. Thus, theapparatus can be downsized.

(3)

In the image projection apparatus described in (1) or (2), a main bodyof the apparatus includes an opening for attaching or detaching thelight source to or from the main body. The opening such as the lightsource replacement opening 53 c is formed at a position of the main bodysuch as a base component 53 facing an installation surface on which themain body is placed.

According to the configuration as such, as mentioned in embodiments, aflow path for cooling the reflector and the horizontal duct 93 as a flowpath for cooling the heat sink 13 are also formed on the base component53. Therefore, it is possible to reduce a width in a directionorthogonal to the projection plane of the projector 1. Furthermore, theheated air of the air flowing in the airflow path 65 moves upward, whilethe lower temperature air moved downward. Consequently, air layers maybe generated in the airflow path. By forming the opening at theinstallation surface of the apparatus, a side (handle portion 68) of theairflow path 65 exposed from the opening is cooled by the lowertemperature air. Thus, the temperature rise of the side (handle portion68) of the airflow path 65 exposed from the opening can be suppressed.When the light source unit 60 is to be removed, the side (handle portion68) of the airflow path 65 exposed from the opening is grabbed orpinched. Therefore, by suppressing the temperature rise of the side(handle portion 68) of the airflow path 65 exposed from the opening, itis possible to grab or pinch the airflow path 65 and remove the lightsource unit from the light source replacement opening 53 c of the mainbody, at an earlier stage from when the light source stops. Furthermore,disposing the airflow path 65 at the installation side of the apparatusmeans that an airflow path for guiding the cooled air to the lightsource is disposed at the installation side. Therefore, it is possibleto reduce an area required for installing the apparatus.

(4)

In the image projection apparatus described in any of (1) to (3), theapparatus further includes an openable and closable cover such as anaccess cover 54 for opening or closing the opening formed for attachingor detaching the light source 61 to or from the main body. Furthermore,the holding member 62 includes an openable and closable cover coolingflow path such as an opening 65 a for flowing air between theopenable/closable cover 54 and the light source 61.

According to the configuration as such, as mentioned in embodiments, thetemperature rise of the openable/closable cover 54 can be suppressed.Thus, it is possible to reduce a time period from when the light source61 stops until when the temperature of the openable/closable cover 54 isso lowered that the user can grab or pinch it, compared with aconventional time period. Thereby, it is possible to remove the lightsource unit 60 from the light source replacement opening 53 c of themain body, at an earlier stage from when the light source 61 stops dueto its end of lifetime. Consequently, the downtime of the apparatus canbe reduced, since the light source unit 60 can be replaced at an earlierstage from when the light source 61 stops due to its end of lifetime.

According to the present invention, the handle portion includes thefirst flow path for flowing air. The air flows into the first flow path,so that the temperature rise of the handle portion due to heatconductance and heat radiation from the light source can be suppressed.Thereby, it is possible to lower the temperature of the handle portionto an extent of temperature allowing for the user to grab or pinch it,at an earlier stage from when the light source stops, compared to theconventional technology. Therefore, it is possible to work on theoperation including grabbing or pinching the handle portion and removingthe light source unit from the light source replacement opening of themain body, at an earlier stage from when the light source stops due toits end of lifetime, compared to the conventional technology.Consequently, the downtime of the apparatus can be reduced, since thelight source unit can be replaced at an earlier stage from when thelight source unit stops due to its end of lifetime, compared to theconventional technology.

Although the invention has been described with respect to specificembodiments for a complete and clear disclosure, the appended claims arenot to be thus limited but are to be construed as embodying allmodifications and alternative constructions that may occur to oneskilled in the art that fairly fall within the basic teaching herein setforth.

What is claimed is:
 1. An image projection apparatus comprising: a lightsource, light from which is used to project an image; and a holdingmember configured to hold the light source, the holding member includingwalls forming a handle portion such that there is a space between thewalls, and the space being a first flow path for flowing airtherethrough.
 2. The image projection apparatus according to claim 1,wherein a main body of the apparatus includes an opening for attachingor detaching the light source to or from the main body, and the handleportion is disposed at a position facing the opening.
 3. The imageprojection apparatus according to claim 2, wherein the opening is formedat a position of the main body facing an installation surface on whichthe main body is placed.
 4. The image projection apparatus according toclaim 2, further comprising: an openable and closable cover for openingor closing the opening; and a second flow path for flowing air betweenthe openable and closable cover and the holding member.
 5. The imageprojection apparatus according to claim 4, wherein a part of a wall ofthe first flow path is also a wall of the second flow path.
 6. A lightsource unit attachable to and detachable from a main body of an imageprojection apparatus, the light source unit comprising: a light source,light from which is used to project an image; and a holding memberconfigured to hold the light source, the holding member including wallsforming a handle portion such that there is a space between the walls,and the space being a first flow path for flowing air therethrough. 7.The image projection apparatus according to claim 1, wherein the firstflow path is open on a first end of the walls and closed on an oppositesecond end of the walls.
 8. The image projection apparatus according toclaim 1, further comprising a holder attached to the light source, theholder including an emitting window via which light from the lightsource is emitted, wherein the holder is further attached to the holdingmember such that the first flow path is open to the holder.
 9. The imageprojection apparatus according to claim 1, wherein a shape of the handleportion is a cuboid protrusion on a side of the holding member oppositeto the light source.
 10. An image projection apparatus comprising: alight source having a reflector; a holder having a first side to whichthe light source is mounted so that the reflector faces the holder; anda bracket fastened to a second side of the holder, the bracket includinga channel that is an air flow path extending in a direction of extensionalong the holder and the light source, and an external side of thechannel being a handle portion.
 11. The image projection apparatusaccording to claim 10, wherein the bracket further includes flangeportions extending away from the channel, wherein the holder fastens tothe flange portions of the bracket such that the channel is open againstthe holder, whereby air flows in the air flow path against the holder.